#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>
#include <string.h>
int main()
{
    char ch[500] = { 0 };
    int count = 0;
    while (scanf("%s", ch) != EOF)//多组输入
    {
        int map[128] = { 0 };//记录出现的字符
        int len = strlen(ch);
        int i = 0;
        for (i = 0; i < len; i++)
        {
            if (map[ch[i]] == 0)//等于0说明该字符未出现过，count++，并标记该字符
            {
                count++;//计数器
                map[ch[i]] = 1;//标记字符
            }
        }
        printf("%d", count);
    }
    return 0;
}